1. Field of the Invention
The present invention relates to (a) an information processor which is used in, for example, a parent device/child device TV system that has as part of a parent device a digital TV having a multi view display function capable of displaying a plurality of video sources, and can transfer at least one video source to a child device monitor provided outside the parent device, (b) a TV system, (c) a control method, and (d) a program.
2. Related Background Art
With digitization of broadcasts and increase in size of view and improvement in fineness in displays, a display form called multi view display in which various video sources are displayed on one display at a time is expected as one of means for using a display as a “window of information in a household”. Some current displays have incorporated therein a function capable of receiving broadcasts of two channels at a time and displaying the same on a screen at a time, and there is a high possibility that the number of received channels and the number of display views will further increase depending on purposes.
If a display enabling such multi view display is used, programs being broadcasted at a same time zone can be viewed on the instant and at the same time, and one program being broadcasted can be viewed while viewing other program previously recorded in a VTR at the same time.
Furthermore, with digitization of broadcasts, the display starts to change from those simply displaying a picture broadcasted unilaterally to those allowing the user to interact with a broadcast station. Typical examples thereof include data broadcasts. The data broadcast has developed from a teletext system providing information unilaterally from a broadcast station in the conventional analog broadcast to the user, and is given new service such as bilateral on-demand type multimedia service. Typical examples of the service include program linkage service, EPG (electronic program guide) service, e-commerce and delivery of data.
The data broadcast has been standardized in Association of Radio Industries and Businesses (ARIB), and details of the data broadcast are described in ARIB Standard (ARIB STD B-24: Data Broadcast Coding System and Transmission System in Digital Broadcast). According to ARIB Standard, the receiver is required to have a function of OSD (On-Screen Display) for smoothly synthesizing into a picture a user interface using drawings (GUI: Graphical User Interface) like a personal computer. The OSD is required not only as display for the above data broadcast but also as display for operation aid for enabling easy control of devices from the display side when a variety of devices (digital camera, digital video, DVD, DVHS, etc.) and pictures from those devices are displayed on the display.
Further, in addition to the above digitization and increase in added value, construction of business models using the display is actively conducted. One example thereof is service based on accumulation by a service provider with a receiver equipped with a HDD (hard disk drive) (delivery of music, delivery of information, e-commerce, etc.).
From this background, functions required for household receivers in future include (1) function of displaying broadcasted pictures of multiple views, pictures from peripheral devices and the like on multi views at a time, (2) function of smoothly displaying OSD such as OSD for data broadcasts, UI (user interface) and the like using drawings and (3) function of coping with accumulation type service, which far surpass just receiving functions of conventional TV and are proceeding toward improvement in function and increase in added value.
However, such tendency for digitization of the display is innovative as to functions and applications of the display, but its cost increases with improvement in function of the receiver. This is one of causes of the fact that spread of digital TV stagnates at present.
Furthermore, there arises no particular problem if a high-functional receiver is installed on a one-per-household basis, but if consumers install digital TV not on “one-per-household basis” but on “one-per-room basis” as in the case of conventional analog TV, a total installation cost significantly increases. Therefore, it is difficult to use digital TV directly as a replacement for analog TV at present.
Further, if digital TV comes into use, there arises a possibility that analog TV or the like that has been used becomes unnecessary, and thus money spent for purchase of analog TV goes to waste.
Focusing on the multi view display function, for example, there may be cases where some digital broadcast sources are unused such as the case where one digital broadcast source is displayed on a full view, in addition to the case where a plurality of digital broadcast sources such as normal display and display of programs on different channels are displayed at a time in a display form of a main view and sub views.
Furthermore, in many households, a main large TV receiver set is placed in a living room where all family members enjoy themselves by sharing the receiver set. Thus, external devices such as a DVD and a VTR are connected to the large TV receiver set, and it is used as a hub of multimedia in the household. Therefore, the large TV receiver set which is shared by family members is often hard to be monopolized by some of the members.
Further, if, when several persons use a large TV receiver set having a multi view display function as described above, some of them display on a sub view a program other than a program displayed on a main view, the main view decreases in size, and thus others may be annoyed.
In this case, a recorder such as a VTR or hard disk recorder may be connected to an external output terminal of the large TV receiver set to record a program so that some persons view the program after others view the program. However, if a video source output from the external output terminal of the large TV receiver set during recording is changed, recording of video contents selected may end in failure, thus making it impossible to view the video contents.
In consideration of these situations, it is preferable that a parent device/child device TV system enabling send/receive with an information processor is constructed using as a parent device a combination of an information processor such as a set stop box as described above and a digital display such as a PDP connected to one specified terminal of the information processor, and further using as child devices an analog TV comprising one or more sub-information processors and displays and the like. If in this TV system, use of a digital tuner, HDD or the like being a video resource in the parent device is assigned to the child device as required using the parent device as a high-functional receiver and using as the child device devices that have been used (analog TV, VTR, etc.), the digital broadcast can be viewed even with conventional devices while keeping a total installation cost at a low level.
One of such TV systems is a home network. In this home network, a plurality of video resources such as tuners are interconnected via network means (e.g., IEEE 1394). In this case, data having a large bandwidth such as video data is generally compressed and transmitted depending on the transmission ability of the network. Furthermore, for the digital broadcast, the tuner part and the HDD can be connected to the network by defining those devices as IEEE 1394 devices (subunits).
For construction of the network, especially LAN (Local Area Network), wireless LAN represented by the standards of IEEE 802.11a/b/g and the like starts to come into wide use in not only enterprises but also households, as means for constructing a network between personal computers, instead of wired LAN by Ethernet® that has been in the mainstream. However, wireless LAN has an advantage in that physical cable wiring is eliminated and an installation place can be freely selected, and therefore it is used as a replacement for wired LAN. Thus, wireless LAN is used mainly for the purpose of data communication at present because of limitation of bands that can be secured.
For such situations, recently, it has been fully possible to pass compressed video data and speech data through wireless LAN owing to progress of video compression techniques such as MPEG 2. Further, with a drop in price of modules used in wireless communication acting as a favorable factor, wireless LAN becomes one of remarkable techniques not only for data communication but also for digital household appliances that can cope with delivery of moving pictures.
As a result of such tendency, wireless LAN has come into use for communication between the parent device and the child device in the TV system using the parent device and the child device described above. One example of such TV systems is a TV system in which TV pictures, audio, internet information and the like which are received by the parent device are transmitted to a child device using wireless LAN and video can be displayed at the child device, and switching between programs at the child device and remote operations of a browser of the Internet are enabled. A technique regarding such a TV system is disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-358966.
FIG. 46 is a block diagram showing the configuration of a TV system using a conventional wireless LAN. In the example of the conventional technique shown in FIG. 46, wireless communication is carried out between one parent device 150 and three child devices 151a, 151b, and 151c. 
The parent device (video transmitter) 150 is provided with a TV antenna 130, mutually independent three tuners 131a to 131c, video processors 132a to 132c, compressors 133a to 133c, a multiplexer 134, a wireless transmitter 135 and a wireless send/receive antenna 136.
In the parent device 150 constructed as described above, a video signal including a plurality of programs is received by the TV antenna 130, and a specified program is selected by the tuners 131a to 131c. Video data is produced from received data of the selected program by the video processors 132a to 132c. Then, the data transmission band is limited to a bit rate allowing wireless transmission by the compressors 133a to 133c. Then, compressed data of three lines is subjected to time division multiplex by the multiplexer 134. The data is subjected to coding, amplification and the like by the wireless transmitter 135, and transmitted via the send/receive antenna 136.
The child devices 151a to 151c are provided with wireless send/receive antennas 137a to 137c, wireless receivers 138a to 138c, multiple dividers 139a to 139c, expanders 140a to 140c and child device monitors 141a to 141c, respectively.
In the child devices 151a to 151c constructed as described above, the video signal transmitted from the parent device 150 is received by the wireless send/receive antennas 137a to 137c, and subjected to processing such as decoding in the wireless receivers 138a to 138c. Then, only required data is separated and derived in the multiple dividers 139a to 139c, and compressed data is decoded by the expanders 140a to 140c. Pictures are displayed at the child device monitors 141a to 141c. 
In this TV system, switching between programs can be performed by controlling the tuners 131a to 131c of the parent device 150 using selection buttons (not shown) provided in the child device monitors 141a to 141c by the user.
By using the TV system employing wireless LAN, the child devices 151a to 151c can freely be installed within a range where wireless communication is possible if the parent device 150 is connected to the antenna terminal even when the place for installation of the antenna terminal and the like on the wall surface is limited in the household and the like, and thus pictures can be viewed without specific limitations on the place.
In the TV system described above, while no display is provided in the parent device, a TV system with a display provided in the parent device is disclosed in, for example, Japanese Patent Application Laid-Open No. H8-79720. In this example of the conventional technique, one tuner is provided in the parent device, and video data broadcasted and tuned is accumulated in a storage device such as a memory. Video is displayed at the display (monitor) of the parent device based on the video data, or video is displayed at the display (monitor) of the child device after it is transmitted to the child device. That is, in this TV system, the parent device is used as if it were a home server of pictures.
However, if a technique for compressing video data is employed for communication between a parent device and a child device, audio/video data compressed in, for example, the MPEG 2 format is treated in a packetted form such as a TS (transport stream). Accordingly, for using an analog device such as a conventional analog TV as the child device, expensive functions such as a demultiplexer for taking desired MPEG 2 data from a TS packet, an MPEG 2 video decoder for expansion and an audio video decoder are required. Thus, in some cases, introduction of a general digital broadcast receiver having no multi view display function as the child device may result in a higher benefit-to-cost ratio. This contradicts the purpose of viewing the digital broadcast at a low cost while using a conventional analog device.
Further, if a GUI menu by OSD display is to be displayed on a view transferred from the parent device to the child device, reprocessing of the TS packet for the purpose of insertion of OSD data as is done with an authoring tool of a broadcast station or the like is required to be carried out at the parent device. This increases the cost of the parent device.
Furthermore, if a program or the like being transmitted from the parent device to the child device is freely changed by the parent device, the picture may be switched unexpectedly so that a desired picture is missed on the child device side.
Furthermore, in the TV system described in Japanese Patent Application Laid-Open No. 2001-358966, tuners, the number of which equals the number of child devices, are required. In this case, if the types of tuners are the same, tuning from one child device inevitably allows one tuner to be occupied, thus eliminating the problem such that requests for tuning from a plurality of child devices go to one tuner and as a result, video resources compete. However, if the types of tuners are different, or multi view display can be provided at any child device, video resources may compete as described below.
(Configuration where Types of Tuners are Different)
As described previously, a transition has been made from analog ground wave broadcasts to BS/CS digital broadcasts, and ground wave digital broadcasts will be operated in near future. If all these broadcasts are to be received, tuners having different broadcast types are required. In FIG. 46, for example, the TV system is constructed with the tuner 131a as a tuner for analog ground wave, the tuner 131b as a BS/CS digital tuner and the tuner 131c as a tuner for digital ground wave.
In this case, even if the number of tuners equals the number of child devices, competition of video resources occur if requests for viewing of BS/CS digital broadcasts at a time from the child devices 151a and 151b, for example, because the types of tuners are different.
(Case where there is a Child Device Comprising a Multi View Function)
If a display terminal having a multi view display function is used, a plurality of video resources may be used at a time for multi view display in the case where there is a child device comprising a multi view display function even if the types of tuners are all the same and the number of tuners equals the number of child devices. This causes shortage of tuners, resulting in competition of video resources.
Furthermore, in Japanese Patent Application Laid-Open No. H8-79720, there arises a problem similar to competition for the tuner between video resources if a plurality of users try to regenerate the picture from a storage device such as a memory.
When competition of video resources (tuners) occurs, a program may suddenly change while the program is viewed, or a program to be viewed may not be selected. In particular, if wireless LAN is involved, child devices, and the child device and the parent device are often at a distance from each other, and therefore a situation may not understood quickly, resulting in significant confusion on operations.
If a required number of tuners different in type are simply provided, competition of video resources can be avoided, but the cost considerably increases, and it is thus impractical.
Further, in the conventional parent device/child device TV system disclosed in Japanese Patent Application Laid-Open No. 2000-181421, a program cannot be selected from the child device to the parent device.
Furthermore, if a program or the like being transmitted from the parent device to the child device is freely changed by the parent device, the picture may be switched unexpectedly so that a desired picture is missed on the child device side, or recording ends in failure on the child device side.
The present invention has been made in view of such problems, and its first object is to provide an information processor enabling a digital broadcast to be viewed at a child device at a low cost, a TV system and a program.
Furthermore, the second object of the present invention is to provide an information processor which can prevent sudden switching of the video displayed at a child device even if a video source of video data being output to the child device coincides with a video source to be used, TV system and a program.
Furthermore, the third object of the present invention is to provide an information processor which can prevent confusion of users of child devices when requests for output of video data included in one video source are made from a plurality of child devices on the video source, a TV system, a control method and a program.
Furthermore, the fourth object of the present invention is to provide an information processor capable of tuning by a child device, a TV system and a program.
Furthermore, the fifth object of the present invention is to provide an information processor which can prevent sudden switching of the picture displayed at a child device even if a video source of video data being output to the child device coincides with a video source to be used, TV system and a program.